A tanker-type truck is conventionally utilized to transport fuel from storage depots to various service stations. Typically, the tanker is divided into a plurality of containers holding various types of fuel. A sight glass is preferably provided in the discharge tube from the tanker so that the flow of fuel may be directly observed by the tanker driver when discharging the fuel into the storage tanks at the service station. In this way, the tanker driver can check that fuel is flowing through the tube, as well as confirm the type of fuel flowing therethrough.
One type of sight glass currently utilized for this purpose is composed of a solid clear cast acrylic substance formed in the shape of a ring. The clear acrylic ring is then fastened between a pair of flanges conventionally found in a connection between two sections of the tanker discharge tube. In this way, fuel flows through the hollow interior of the clear acrylic ring for viewing by the tanker driver.
It is not uncommon to find additives mixed in with conventional fuel products in order to raise the octane level of the fuel. Such additives, such as MTBE, have been found to dissolve, craze, or optically cloud the acrylic material, thereby reducing the effectiveness of the material as a sight glass. Acrylic is preferred material for use as a sight glass in fuel lines, since the material is clear, yet more resistant to breakage than glass.
It is therefore a general object of the present invention to provide an improved sight glass for fuel lines.
Another object of the present invention is to provide a sight glass which is resistant to fuel additives.
Still another object is to provide a sight glass which may be formed of solid acrylic yet is sealed from fuel additives.
These and other objects will be apparent to those skilled in the art.